How the Schwalbe Procore system works
The actual Procore system consists of the (open) Inner tyrea separate Hose with special dual valve and the Airguidewhich guides the air from the valve into the outer chamber. The Procore inner tyre is visually similar to the carcass of a road bike tyre, but is a completely new construction. A light butyl tube holds the air inside. The blue inner tyre is placed on top of this. As the inner tyre is not loaded when rolling, Procore has no effect on rolling resistance. As the Procore bead cannot rest on the rim flange, but only on the outer tyre bead, the inner tyre has a particularly low-stretch bead core that remains securely in place even at six bar.
Procore is compatible with any Tubeless-ready outer tyres can be combined. To seal this, you need the normal amount of sealing milk (60-80 ml).
Dual valve: How to fill both chambers with air
Ingenious and simple at the same time. The position of the blue anodised valve attachment ("selector") determines whether the inner tyre tube (top) or the outer tyre chamber (bottom) is inflated. In the latter case, the air flows out through the small hole at the side.
Advantages and disadvantages of Schwalbe Procore at a glance
+ Low pressures of 0.8 to 1.25 bar in the outer tyre provide extremely high traction and very sensitive "primary suspension" without the tyre buckling
+ Maximum compatibility, as it can be retrofitted to any rim from an inner width of approx. 23 mm (26", 27.5" and 29er) and can be combined with any tubeless-ready tyre
+ Very high puncture protection and extremely good emergency running properties, as Procore stabilises & fixes the tyre on the rim
+ Facilitates tubeless mounting of the outer tyre through active sealing
- 50 to 200 grams more weight per tyre compared to conventional systems
- Somewhat more complex, as two tyres have to be fitted, the Airguide and inner tyre have to be aligned and two air chambers have to be inflated and checked per tyre
Presented at Eurobike 2014, now in the shop
Under 1 bar pressure in the MTB tyre? And thus puncture-free through rough terrain? Schwalbe's Procore system should make this possible. The development was celebrated at Eurobike as one of the most innovative new products. The concept behind it is very simple: low tyre pressures provide more traction, more control and more comfort in MTB sports - and depending on the terrain, even less running resistance. Unfortunately, this also greatly increases the risk of punctures. At around 1.5 bar at the latest, that's the limit if you don't want to risk constant punctures. Schwalbe and Syntace have therefore joined forces to work on a solution: A dual-chamber system with a low-pressure outer tyre and a smaller high-pressure inner tyre - this principle has long been established in motocross sport.
After almost two years of joint development work, Schwalbe presented the production-ready system to the public at Eurobike. All kinds of ideas were tried out and concepts discarded along the way, such as a solution with two separate valves. "We always realised that the acceptance of this otherwise ingenious concept would suffer - after all, not everyone wants to drill a second hole in their beautiful rim," says Markus Hachmeyer, head developer at Schwalbe. For this reason, a single-valve solution was always being worked on in parallel.
Extensive prototype tests were carried out before the system was presented to the public. "In terms of riding performance, the dual-chamber system was a success right from the start. Every Gravity and Enduro Team rider who was fitted with it was simply thrilled with the puncture protection, the additional traction and the smooth riding behaviour," reports Hachmeyer. In most cases, the riders more than made up for the weight disadvantage: "With Procore, they were able to ride lighter rims and often lighter tyres too." An argument that may work in the gravity sector, but does not apply to the ranks of already weight-optimised CC and marathon bikes. There, Procore in its current form inevitably means a considerable increase in weight. Whether Procore will therefore find its place primarily in the gravity segment remains to be seen. The advantages should also be extremely tempting for touring bikers and Alpine crossers.
Tubeless vs. Procore: Test in the test lab
Spring characteristics: Similar to a suspension fork, pneumatic tyres also have a measurable suspension characteristic. The black line shows a standard tubeless set-up. In contrast, the outer tyre equipped with Procore (green line) compresses noticeably more under the same load due to the low operating pressure. This increases both comfort and traction. Later, the high pressure inner tyre provides the necessary puncture protection: the kink in the bend.
Schwalbe Procore in weight comparison:
The main disadvantage of Procore is that a bike fitted with Procore currently weighs around 400 grams more than a tubeless setup.
Schwalbe Procore in a practical test
Rarely has it been so difficult to get a test sample in time. And rarely has the curiosity before the test been as great as with this Inno-Check. Prepared for the worst, the installation and handling turned out to be extremely foolproof. For tubeless riders, it is even a relief, as there is no more shaking until the tyre seals. The inner tube actively presses the tyre onto the rim and thus seals the system automatically - so you can even inflate tubeless tyres with a hand pump! Our pre-production samples still had small deficits: The seal on the selector attachment of the valve is still a little too thin, causing the inner chamber to gradually lose air. Schwalbe assures us that this will be rectified in series production. Regardless of this, double attention is required with Procore - in future you will have to check the air pressure in four chambers (two per wheel) before setting off.
The revelation awaits on the trail. Once you're surfing the trail with 0.8 to 1.2 bar in the outer chamber, you'll be amazed - endless traction and an almost unreal glide over the trail. Procore has already soaked up small bumps and sloping roots before the suspension fork or shock can even react. In rough terrain, the micro-suspension of the tyres and the macro-suspension of the suspension elements complement each other perfectly. Loose gravel and gravel packs are absorbed almost completely. Sudden loss of air when leaning and cornering - a dreaded phenomenon with conventional tyres with low air pressure - does not occur with Procore. The only point of criticism: the steering behaviour on the road or on flat, hard surfaces, which takes a little getting used to. Puncture protection? Exemplary! Even heavy full-speed rides over scree fields and root trails couldn't push Procore to its limits. And if you do get a puncture in the outer tyre, the rider has emergency running properties at his disposal that would make any tubular tyre rider green with envy. First ride impression - unfortunately awesome!
Tips for mounting Schwalbe Procore
As the standard Procore does not require a second valve, it is compatible with any rim from approx. 23 mm internal width. However, there are still a few things to consider when fitting. We'll show you how.
Tip: The valve area is a critical point. If the outer tyre loses air here, it often helps 1) to inflate the inner tyre a little more, 2) to tighten the lock nut on the valve and 3) to direct the sealing milk here by shaking. Then it works.
Conclusion on the Schwalbe Procore system
Procore kills several birds with one stone. Carefree riding with incredibly low pressures, outstanding traction and a huge increase in comfort. Even at under 1 bar pressure, the tyre remains stable when cornering, and if the outer tyre does lose air, you can roll home on the inner tyre. Incidentally, the inner tyre also helps to seal the tubeless system - regardless of the rim and tyre. The system will quickly establish itself among gravity riders. Touring bikers have to weigh up the pros and cons: Are traction and puncture protection more important, or lightweight construction? The choice is yours!
PROCORE complete setProcore will initially only be available as a complete set for one bike - with two Procore inner tyres (blue), special inner tubes, air guides, sealing milk, mounting fluid and tyre levers. Later also individually.
Info www.schwalbe.com
Price 179 euros (expected at the beginning of 2015)
Formats 26", 27.5'' and 29''
Compatibility can be combined with all rims from approx. 23 mm inner width upwards, and with all tubeless-ready tyres
